The present invention generally relates to hypodermic needle devices for collecting samples of blood or other body tissue. In particular, the present invention relates to such devices that conceal the sharp point of the hypodermic needle following use.
A hypodermic needle entering into a patient""s body is invariably contaminated by the patient""s blood and body fluids. Following use of the needle, the needle presents a risk to physicians, nurses, and other health care personnel because the needle might transmit an infection or disease to such personnel if it were to accidentally puncture them. Thus, health care personnel are in constant danger of contracting infections and diseases, some of which may be deadly. Other potential victims of accidental needle punctures include sanitation workers who later dispose of garbage containing the hypodermic needles. Often a needle puncture in a person""s skin is so trivial that it remains unrecognized until the person becomes seriously ill. The diseases which may be transmitted by a contaminated hypodermic needle include Immune Deficiency Virus, Hepatitis, Rabies, Cure, Encephalitis, and Arbor viruses. The outcome of contracting one of these diseases is often fatal because there are no known cures for any of these diseases.
The problem of accidental needle punctures is well recognized, and enormous inventive effort has been devoted to concealing the sharp needle point of hypodermic needles. One such effort is described in the present applicant""s U.S. Pat. No. 5,338,311, issued Aug. 16, 1994, and 5,514,100, issued May 7, 1996. A hypodermic needle has many applications in modern medicine. One application is to fit the hypodermic needle onto a syringe so that the needle can be inserted into a person""s body or vein to obtain samples of tissue or blood for examination. To obtain multiple samples for different tests, a double-ended hypodermic needle is attached to the syringe barrel. One sharp end of the needle is used to puncture the vein of the patient, while the other sharp end projects inside the syringe barrel. A pre-vacuumed test tube with a rubber stopper is forced on the needle end inside the barrel. Puncture of the rubber stopper results in the withdrawal of a blood sample into the test tube because of the preexisting vacuum. The test tube containing the blood sample is then withdrawn, and another test tube intended for a different test is forced into the barrel to collect a second sample in an identical manner. The barrel with the attached needle is disposed of in its entirety, but during its transport to final destruction it may cause accidental needle sticks and transmit diseases.
The double-ended needles pose special problems because retraction of one sharp end can result in the projection of another sharp end toward the user. Further, the needle may be screwed to the end of the barrel, which makes retraction of the needle difficult or impossible.
A primary object of the present invention is to provide an improved blood sample collection assembly that conceals the sharp needle point after its use.
One specific object of this invention is to provide an improved blood sample collection assembly which provides good structural stability for the mechanism that is used to retract the needle after it has been used.
Yet another object of the present invention is to provide such an improved blood sample collection assembly which facilitates fabrication, and reduces the cost, of the assembly.
Still another object of the present invention is to provide such an improved blood sample collection assembly which facilitates the operation of the assembly, particularly during retracting movement of the needle.
Another object of the present invention is to provide such an improved blood sample collection assembly which improves the acceptability of the assembly by providing an external appearance which is virtually the same as that of conventional hypodermic needle blood sample collection assemblies which do not provide for needle retraction.
A further object of the invention is to provide such an improved blood sample collection assembly that operates in a fail-safe manner in that the retraction mechanism must be actuated by conscious effort, and the retracting movement automatically stops when both ends of the double-ended needle are concealed.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the accompanying drawings.
In accordance with the present invention, the foregoing objectives are realized by providing a hypodermnic-needle sample collection device comprising an elongated, generally cylindrical barrel forming an aperture at the distal end of the barrel and opening into the interior of the barrel; a needle holder mounted for longitudinal movement within the barrel, the needle holder including a pin projecting laterally therefrom; a hollow needle carried by the needle holder and projecting from the holder along the axis of the barrel; and guide means forming longitudinal linear and spiral guide surfaces extending along at least a portion of the length of the barrel for engaging the pin and moving the needle longitudinally within the barrel in response to relative rotational movement between the linear and spiral guide surfaces.
In a preferred embodiment of the invention, the guide means comprises a guide tube telescoped within the barrel, the opposed walls of the guide tube and barrel forming cooperating spiral and longitudinal slots receiving the laterally projecting pin. The guide tube and barrel are rotatable relative to each other so that one of the side walls of the spiral slot cams the pin along the longitudinal slot when the guide tube and barrel are rotated relative to each other. The guide tube preferably forms the spiral slot, and the barrel forms the longitudinal slot, with the longitudinal slot being open on the interior surface of the barrel and closed on the exterior surface of the barrel, and the pin terminating within the longitudinal slot.